doc: clarify the behavior of Buffer.byteLength

seishun · jasnell · commit 8a078c820e11 · 2017-03-07T10:43:22.000-08:00
PR-URL: #11238 Refs: #11165 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Michaël Zasso <targos@protonmail.com>
diff --git a/doc/api/buffer.md b/doc/api/buffer.md
@@ -618,6 +618,10 @@ Returns the actual byte length of a string. This is not the same as
 [`String.prototype.length`] since that returns the number of *characters* in
 a string.
 
+*Note* that for `'base64'` and `'hex'`, this function assumes valid input. For
+strings that contain non-Base64/Hex-encoded data (e.g. whitespace), the return
+value might be greater than the length of a `Buffer` created from the string.
+
 Example:
 
 ```js
